Lubricating composition



Patented Apr. 29, 1952 i Y I UNITED STATES PATENT ore-ice LUBRICA'IIN G COMPOSITION Arnold J. Morway, Clark Township, Union County, and David W. Young, Roselle, J.,

assignors to Standard Oil Development Company, a corporation ofDelaware No Drawing. Application May24, 1950, Serial N 0. 164,034

5 Claims. to]. sea-42. 1)

1 This invention relates to lubricating composietc. The alkali metal :soaps of the saturated tions and particularly to lubricating greases 'havacids such as hydrogenated fish oil acids, s'tearic ing outstanding oxidation resistance properties. acid, Ihydroxy stear'ic acid, hydrogenated beef More particularly this invention relates to a .fat 'andtallow, or the glycerides of variousfatty lubricating grease composition comprising a m n- 5 acids or mixtures of these in any proportionmay eral base grease containing a small proportion ibe us d,

of a bis-phenol sulfide as an oxidation inhibitor. Although the percentages of the anti-oxidant It is well known in the art of lubricating grease utilized in this invention may vary depending manufacture that the resistance of grease comupon the use .to which the grease composition is positions to oxidation may be increased by addto be placed, an operable percentage range would ing to the grease composition small percentages .be from 0.1% to 2.0% by weight 0f t mp of oxidation inhibitors. Various oxidation in- "oxidant, preferably 0.5% to 1.5% by weight; hibitors are well known in the art, examples :be- The grease compositions of this invention are ing phenyl alpha naphthylamine, phenyl beta prepared according to the following procedure: n'aphthylamine and other amine type compounds The mineral lubricating oil is admixed with a and intermediates and various of the alkylated preformed soap, or soap stock formed in situ in phenols and phenol derivatives. :the mineral oil'by saponification or neutralization .It -has now been found that grease composiof fats or acids respectively, in a grease kettle tions containing minor amounts of bis(5-methy1- equipped for heating by eithera steam jacket or '2- hydroxy phenyl) sulfide, referred to hereinby a direct flame. The temperature of the mixafter Simp y as'b 's p'henolsulfide, have outstandture is raised with stirring 'to one in the neig ing oxidation resistance properties. 'borh'oodof 400 to 500 After the soap has beh bis-Phenol Sulfide Compound utilized in the come completely dispersed in the oil the heat r s c mp n f this i v n i n wa pr is out "and the desired additives are added to pared as follows: .25 the molten grease, the mixing being continued 109 'g. oflp-c esol W is i ed i 500 C of during this addition. The resulting grease coin- .petroleum ether- A solution of 55 of 2 in position is then pan cooled or cooled in a continu- 6- oco petreleum ether W pp in -ous grease cooler according to standard proceins one w The mixture s a l w d to stand dures. If it is desired to formulate the soap in ov r h petroleum ether leyerwns then go si tu, the desired amount of the saponifiable ma- .pou e ofi r m th r wn mii ma n tori-a1 is admixed with a portion of the mineral thetic oil base greases, particularly those of the the m rystallized from 100 g. of to uen oil-and thedesiredmnal base, usually in the form 27 of a Wh te c y t e powder was obtained. of the hydroxide, is added. After complete sa- Successive crystallizations from 100 c. c. of toluponification th b l c of th i r l oil i ene and 100 .c. c. of glacial acetic acid yi l .3 added and the temperature raised to the meltodor ess C y of y12-hydroxy ing pointof the soap. The desired anti-oxidant p yl) sulfide, melting point 114 C- o 1 C- is added to the grease composition just before the Although it is preferred in this invention to grease is o l d,

incorporate the b s-p Sulfide composition a The concept of this invention will be more an anti-oxidant, the meta'lsalts of this compound 40 clearly explained by reference to the following:

may also be used e t r alone 01 in Comb i Various lubricating grease compositions were With the compounds themselves. The preferred prepared according to the method outlined above embodiment of the invention contemplates incori th following f rmulation:

porating the anti-oxidants into mineral oil base 0" 1 a lubricating grease composltlons although 63.08 a mineral 011 having a viscosity at 2-0 F.

of '55 S. U S. synthetic tester type oils, may be used. 8; 23:22: 3 guide The mineral oils used as a base for the .lu'bri- 0 f a tum i 8 ml art" f sod um 8 1- cating compositions contemplated may be thickf i 1 p e 0 u ened to a grease consistency with any of the well 1 51 31 3 Pa 2% t known grease making soaps-such as soaps of the 0 e e 116 an alkali or alkaline earth metals. Especially desir- A t 1 deactivator of th hei te type may also able are the alkali metal soaps of unsaturated be present if desired. acids such as those contained in rape seed oil, It is to be noted, of course, that varying lard oil, soya bean oil, cotton seed oil, fish oils, amounts of the percentages given may be used in order to change the properties of the final grease composition. This variance is in accordance with techniques which are familiar in the art.

The experimental grease compositions of this invention were then subjected to the standard Norma-Hoffman oxidation bomb tests. The data on the compositions of this invention are reported in Table I below as hours necessary to obtain a certain pressure drop. As is well understood in the art, the greater the length of time necessary to obtain a certain pressure drop, the more stable a grease composition is to oxidation.

TABLE I Norma-Hofimcm oxidation tests on mineral oil experimental greases Hours for Pressure Drop of- Anti-oxidant Used None 46 52 h 06 I 2,6,di-tcrt.-Butyl p-cresl 60 110 140 174 II 2,6,di-phenyl ethyl p-crosoL -16 50 180 III Mixture of diand tri-tcrt.-

octyl phenol 18 28 42 114 iV Tert.-octyl phenol alkylated with isobutylcne 3O 54 168 V 2,2-bis(2-hydroxy-3,tort.-Bul 1 tylmethylphenyl) propane (52 i 100 140 VI l,4-bis(3,-i dihydroxy bcnzone) 2,3 dimcthyl butanc 16 i 20 46 60 88 116 VII bis(5 methyl 2,hydr0xy phenyl) sulfide ms 1 144 178 274 It will be seen from the data reported in Iable I that the bis-phenol sulfide composition of this invention has outstanding properties as an oxidation inhibitor, it requiring 96 hours to reach a 5 pound pressure drop and 2'74 hours to obtain a pound pressure drop with a grease containing this inhibitor.

The phenolic type oxidation inhibitors are generally unstable in the presence of sunlight and form lay-products which impart to grease compositions an undesirable darkening efiect. Various samples of grease compositions containing different phenolic type inhibitors are compared, in Table II, with a grease" sample containing the compound of this invention as to stability towards sunlight. It will be seen by an examination of the results given in Table II that whereas the other phenolic type inhibitors resulted in sample darkening after 60 days in sunlight, no change in the color of the grease was obtained when the bis-phenol sulfide was used as the oxidation inhibitor.

TABLE II Light stability of experimental greases goflor (iolor x c e ore ter Anh-Oiidaut (lfi; by at.) Exposure 60 days to Sunlight Sunlight None clear dark. I 2,6,di-tert. Butyl p-crcsol 0 Do. if 2,6,di-phcnyl ethyl p-cresol do Do. III Mixture oi diand. tri-tert.-octyl phenol... do Do. iV tEltnOCtYl phenol alkylatcd I isobutcne .do Do. v 2,2-bis(Q-hydroxy-IS-tcrt.-Butyl-5- Ludo Do.

methly phenyl) propane VI l.4, bis(3,4-dihytiroxy bonzcne)2,3

dhnethyl butane do Do. VII bisQ-rnerhytlhyd \y phenyl) sullfido .d0 no change.

to a grease consistency with an alkali metal soap of an unsaturated fatty acid having combined therein a minor but oxidation resistant improving amount of bis(5-methyl-2-hydroxy phenyl) sulfide.

3. A lubricating grease composition consisting essentially of a mineral lubricating oil thickened to a grease consistency with an alkali metal soap of an unsaturated fatty acid having combined therein from 0.1% to 2.0% by weight of bis(5-methyl-2-hydroxy phenyl) sulfide.

4. a lubricating grease composition consisting essentially of a mineral lubricating oil thickened to a grease consistency with an alkali metal soap of an unsaturated fatty acid having combined therein from 0.5% to 1.5% by weight of bis(5 methyl-Z-hydroxy phenyl) sulfide.

5. A lubricating grease composition consisting essentially of a mineral lubricating oil having a viscosity at 210 F. of 55 S. U. S. thickened to a grease consistency with the sodium soap of rape seed oil having combined therein from 0.5% to 1.5% by weight of big (5-methyl-2-hydroxy phenyl) sulfide.

ARNOLD J. MORWAY. DAVID W. YOUNG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,085,045 Rosen June 29, 1937 2,361,806 Merrill Oct. 31, 1944 2,389,090 Shields Nov. 13, 1945 2,409,303 Morris et a1 Oct. 15, 1946 2,460,025 McNab et a1. Jan. 25, 1949 2,518,379 Rogers et al. Aug. 8, 1950 

1. A LUBRICATING GREASE COMPOSITION CONSISTING ESSENTIALLY OF A LUBRICATING OIL THICKENED TO A GREASE CONSISTENCY WITH A METAL SOAP OF A FATTY ACID HAVING COMBINED THEREIN A MINOR BUT OXIDATION RESISTANCE IMPROVING AMOUNT OF BIS(5METHYL-2-HYDROXY PHENYL) SULFIDE. 